Field of the Invention
The present invention relates to an electronic shift system for a vehicle using a smart key, which enables a driver to perform shifting using a card-type smart key.
Description of Related Art
In general, a vehicle, equipped with an automatic transmission, enables a gear of a target shift range to be automatically operated by controlling hydraulic pressure within a preset shift range depending on the driving speed of the vehicle.
The automatic transmission makes a gear ratio using a hydraulic circuit, a planetary gear, and frictional elements, in order to implement shifting. A Transmission Control Unit (TCU) is in charge of the control of these components.
A Shift By Wire (hereinafter referred to as “SBW”) system is an electronic shift system for a vehicle that includes no mechanical connection structure, such as a cable, between a transmission and a shift lever, unlike a conventional mechanical shift system. In the SBW system, electronic transmission control is implemented in such a way that, when a sensor value, generated when an electronic shift lever or a button is operated, is transmitted to a Transmission Control Unit (TCU), a solenoid or an electric motor is operated by an electronic command signal from the TCU to apply hydraulic pressure to a hydraulic circuit of each shift stage, or to intercept the hydraulic pressure.
Accordingly, the SBW-based automatic transmission has the advantage of enabling easier implementation of shifting to, e.g., a Drive (D), Reverse (R), Neutral (N), or Park (P) range by transmitting an electrical signal, which indicates the driver's shifting intention, to the TCU via the simplified operation of the electronic shift lever or the button. In addition, the SBW-based automatic transmission has the advantage of providing a wide space between the driver's seat and the passenger seat because a reduction in the size of the shift lever is possible.
Meanwhile, a lever-type electronic shift system, which implements shifting using a lever, has no remarkable advantage compared to a mechanical shift system because the shift lever is operated similar to a mechanical shift lever. Moreover, the lever-type electronic shift system is disadvantageous in that it still occupies a large console space, thus causing a relative reduction in the space for peripherals such as, for example, a cup holder and, in particular, in that the protruding lever may thrust the passenger's body in the event of an accident, thus inflicting injury on the passenger.
In addition, a button-type electronic shift system, which implements shifting using buttons, has the advantage of providing easier shifting than the lever-type electronic shift system and the efficient utilization of console space because the installation position thereof can be freely changed to another position (e.g., the center fascia), rather than the console, and also has the advantage of having no risk of contact with the passenger's body in the event of an accident, thus preventing injury of the passenger. However, the button-type electronic shift system requires a large number of buttons because different buttons are used to operate the respective shift stages P, R, N, and D, which is inconvenient to operate. In particular, the large number of buttons is disadvantageous in terms of layout.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.